This invention relates to torque transmitting tools of the type having a drive stud shaped to receive and release a tool attachment, and in particular to an improved quick release mechanism for securing and releasing a tool attachment to and releasing it from the drive stud.
U.S. Pat. No. 5,644,958 describes an effective quick release mechanism for securing tool attachments such as sockets to torque transmitting tools such as wrenches and extension bars. In the disclosed mechanism, the tool includes a drive stud which defines a diagonally oriented opening, and a locking pin is positioned within the opening to move in the opening. In its engaging position, a first end of the locking pin engages a recess in the socket to lock the socket positively in place on the drive stud. When the operator moves the pin in the opening, the first end of the pin is moved out of contact with the socket, and the socket is released from the drive stud.
In the disclosed mechanism of U.S. Pat. No. 5,644,958, the locking pin is biased downwardly by a spring that bears against a large shoulder 52 on the extension bar. This approach requires that the extension bar under the spring be machined or otherwise formed to a substantially smaller diameter than the relatively large-diameter portion of the extension bar immediately above the shoulder 52.